Phosphoramidates



United States Patent 3,335,129 PHOSPHGRAMIDATES Herwart C. Vogt, Grosse lie, and John T. Patton, J12, Wyandotte, Mich, assignors to Wyandotte Chemicals Corporation, Wyandottc, Micln, a corporation of Michigan lo Drawing. Griginal application Nov. 21, 1963, Ser. No. 325,486, new Patent No. 3,256,249, dated June 14, 1966. Divided and this application Sept. 27, 1965, Ser. No. 490,716

12 Claims. (Cl. 260234) ABSTRACT OF THE DHSCLOSURE The phosphoramidates are prepared by the reaction of amidophosphorochloridates with an appropriate polyol containing from 2 to 8 hydroxyl groups. The phosphoramidates are particularly useful in preparing fiame retardant resins.

This is a division of application Ser. No. 325,486 filed Nov. 21, 1963, now US. Patent 3,256,249.

This invention relates to certain phosphoramidates and to polymers prepared therefrom. More particularly, the invention relates to phosphoramidate polyols containing at least one, and preferably two or more hydroxyl groups, which polyols may be reacted alone or in the presence of other polyols with organic polyisocyanates to obtain polyurethane resins having enhanced flame resistant properties.

The reaction of an organic diisocyanate with an organic compound containing at least two hydroxyl groups to produce poly-urethane resins is well known. A relatively new and expanding use for polyurethane foams is in the building and insulation fields. In many of these applications, it is desirable, and in some instances necessary, that the foam be non-burning or flame retardant.

To enhance flame retardancy, various organic and inorganic materials, and more particularly halogen, nitrogen and phosphorus-containing compounds, have previously been added to the reaction mass during the polyurethane forming reaction. Thus, additives such as trichloroethyl phosphate, dialkyl phenyl phosphonate, ammonium phosphate, etc., have been utilized as physically bonded flame retardant agents. However, this expedient has never proven to be Wholly acceptable for several reasons. Oftentimes such additives are not compatible with the foaming ingredients and/or the finished foam. These flame retardant agents may have a plasticizing action and tend to degrade foam properties. Still another disadvantage is that since these additives are only loosely physically bonded to the foam, they are subject to bleeding and migration, leading to -a non-homogeneous composition. Moreover, many of the solid inorganic additives tend to settle out of solution and also may be abrasive to pumps and the metering system during foam preparation. Also, such additives are deleterious in that they tend to embrittle the finished foam. Another disadvantage with these prior art systems is that an inordinate amount of additives is required to realize any significant degree of flame retardancy.

It is an object of this invention to provide poly-functional phosphoramidates. Another object is to provide polyurethane resins containing chemically bonded phosphoramidates, which resins have a high degree of fire retardancy. Another object is to provide economical methods of obtaining fire retardant polyurethane foams, especially of the rigid type.

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The polyhydroxy phosphoramidates provided by this invention may be broadly represented by Formula I:

Where R, together with attached oxygen is the residue of a polyol selected from the group consisting of organic polyols containing at least 2, preferably 3 to about 8 hydroxyl groups per molecule, and polyethers of said organic polyols; R and R may be the same or different and represent a hydrocarbon group such as alkyl, aryl, cycloalkyl, alkaryl, aralkyl containing up to about 12 preferably up to 8, carbon atoms and the foregoing hydrocarbons substituted with one or more halogen atoms, preferably chlorine or bromine; n is a number from 1 to 2, m is a number from 0 to about 7, and is equal to the number of hydroxyl groups present in polyol residue R, f is an integer greater than 1 and is equal to the number of hydroxyl groups originally present in said polyol; (fm) is equal to at least 1; Y is selected from the group consisting of R containing (f-l) hydroxyl groups, and

where R, R, R", Y, j and n have the same significance as stated above and R contains (f-Z) hydroxyl groups, and wherein the molecule contains at least one and preferably two or more hydroxyl groups.

The hydroxyl-containing phosphoramidates of this invention are obtained by reaction of amidophosphorochloridates with an appropriate polyol containing 2 to 8 hydroxyl groups. The reaction is carried out in the presence of a hydrogen chloride acceptor, at temperatures ranging from about 0l00 C. and above, and preferably at C. The reaction is conveniently conducted at atmospheric pressure. Suitable hydro-gen chloride acceptors include tertiary amines, such as trialkyl amines, pyridine, alkali metal carbonates, etc. The amines are preferred for they also serve to act as a solvent for the system and give a coarser salt which can be easily removed by filtration.

The amidophosphorochloridates used to prepare the compounds of this invention are known materials and methods for their preparation are well established. Generally, they are prepared by reaction of a phosphorous halide such as phosphoryl oxychloride with a secondary amine. See for example Organophosphorus Compounds, John Wiley & Sons, Inc., New York, Chapter 10, and US. 2,752,392. The amidophosphorochloridates may be represented by Formula III:

wherein n is equal to 1 or 2 and R and R have the same meaning as stated above.

The polyols that are employed in the reaction with the amidophosphorochloridates to obtain the phosphoramidates of this invention contain at least 2 and preferably 3 hydroxyl groups. Typical of these materials are the glycols, such as ethylene glycol, propylene glycol, trirnethylene glycol, hexamethylene glycol, etc., glycerol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol, manitol, su-

crose, fructose, dextrose, a-methyl glucoside, etc. and alkylene oxide adducts of the foregoing.

From the foregoing, it is evident the preferred polyols employed include polyhydroxyalkanes containing 3 to 8 hydroxyl groups per molecule, saccharides such as monoand disacchardies containing from 5 to 8 hydroxyl groups per molecule, and monoand polyethers of the foregoing.

The preferred polyols are polyethers obtained by reacting any of the foregoing polyhydroxyl materials with an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, 1,1,1-trichloropropylene oxide, etc., or mixtures thereof. The reaction to prepare the polyethers is carried out in the presence of a conventional oxyalkylation catalyst such as BF amines, alkali metal hydroxides and alcoholates, etc., preferably sodium or potassium hydroxide. The, oxinane ring of the alkylene oxide is opened and reacts with a hydroxyl group of the polyhydroxyl compound to generate an ether linkage and a hydroxyl group. The reaction employing ethylene oxide as an example is as follows:

The products may further react with each other or with fresh reactants to produce a phosphoramidate having the following structure:

OR(OH)2 Any of the hydroxyl groups of this material may further react with additional phosphor-ochloridate to further in-' crease the size of the phosphoramidate molecule to yield product mixtures encompassed by Formula I.

It is also possible that if a polyol having vicinal hydroxyl groups is reacted with the phosphorodichloridate,

in addition to obtaining a linear product as depicted above cyclization may occur to yield'a cyclic compound as follows:

R fi ([)H ()H 011 N -P-Ol2+-CCC l In the foregoing Formulae IV-VI, R, R and R" have the same significance as previously stated.

It is obvious from the foregoing that various reactions can occur, yielding a mixture of complex products. Normally the product can be represented by Formula I above wherein the composition has an average molecular weight of from about 300 to 10,000 or more.

The preferred phosphoramidates provided by this invention are obtained by reaction of bis(amido)phosphorochloridates with a polyol having at least 3 hydroxyl groups:

* phosphoramidate radical. The ratio of reactants Will determine the degree of substitution on the polyol nucleus.

Any of the foregoing phosphoramidates and mixtures thereof with conventional polyether polyols or polyester polyols may be reacted with a suitable organic isocyanate to provide the polyurethane resins of this invention. The hydroxyl groups of the phosphoramidates react with NCO groups and thus urethane resinscontaining chemically bonded phosphorus and nitrogen atoms are obtained.

In order to propagate chain growth, the phosphoramidate must contain at least 2 hydroxyl groups. Thus, the reaction product of a phosphorochloridate .with a diol to yield a monohydroxy-containing compounds can be used in minor proportions to control molecule size and to serve as a chemically bonded flame retardant agent. The reaction product of a triol with a phosphorodichloridate yields -a product containing 2 hydroxyl groups andthereby enters the polymerization reaction.

Methods of preparing the novel phosphoramidates of this invention are illustrated by the following examples wherein, unless stated otherwise, all compositions specified are in terms of weight percent.

EXAMPLE I To a 2-liter flask equipped with a stirrer, dropping funnel and condenser was added 171 grams of bis(dimethyl-amido)-phosphorochloridate, 131 grams of triethylamine and 1 65 grams of triethylene glycol. The mixture was heated to about 55 wherein some precipitate formed and the reaction mixture became slightly darker. Nitrogen was bubbled through the system and the reaction mass was heated at 5580 for a period of about 6 /2 hours. Three hours after the initial heating, an additional 71 grams of triethylamine was added to the reaction mass. At the completion of the reaction, the precipitated triethylamine hydrochloride wasfiltered, leaving 749 grams of a dark brown liquid. This material was stripped at 35 C., at 1-2 mm. Hg pressure. 311 grams of the desired product was obtained. An infrared spectrum on this material Was in complete agreement with the structure:

This material is monofunctional, i.e., it has one hydroxyl group, and thus may be included in the urethane forming reaction to provide a chemically bound flame retarding agent.

To a reaction flask, as in Example I, are charged 682 grams of bis(dimethylarnido)phosphorochloridate, 1060 grams of Pluracol SP-560 Polyol, 630 grams of triethylamine and 31 grams of activated carbon bone black. Pluracol SP-560 is a polyether polyol obtained by condensing sorbitol and propylene oxide to yield a product having 6 hydroxyl groups, a molecular weight of about 514, a hydroxyl number of about 654 and an acid number below 1. It is available commercially from Wyandotte Chemicals Corporation. Nitrogen was bubbled through the system and the mixture was heated at 80-100 for about 6 /2 hours. An additional 179 grams of triethylamine was charged, and the reaction mass was heated at 6678 for an additional 4 /2 hours. The solution was then filtered through a Buchner funnel having a diatomaceous earth bed and the filtrate stripped at 70 C., 2 mm. Hg pressure. After refiltering, 850 grams of a product was obtained, the major portion of which corresponded to wherein (SP560) contains five hydroxyl groups and together with attached oxygen is the residue of Pluracol SP-5 60 polyether described above.

EXAMPLE III 1632 grams of Pluracol PeP-450 Tetrol, 682 grams of bis(dimethylamido)phosphorochloridate, 43 grams of activated carbon, and 510 grams of triethylamine were charged to a reaction flask. Pluracol PeP45O is a pentaerythritol-propylene oxide adduct having an average molecular weight of 400, a hydroxyl number of 560 and an acid number of 0.05. It is available commercially from Wyandotte Chemicals Corporation. While passing nitrogen through the system, the reaction mixture was heated at about 80 for 6 /2 hours and an additional 300 grams of triethylamine were added. The mixture was heated for an additional 3 hours and then filtered. 23 grams of diatomaceous earth were added to the reaction mass prior to filtration. The filtrate was stripped at 1-8 mm. pressure at 70-80 for about 5 hours. A product was obtained corresponding to the structure:

EXAMPLE IV To a reaction flask were charged 341 grams of bis (dimethylamido) phosphorochloridate, 21 grams of activated carbon, 27 0 grams of triethylamine and 675 grams of an adduct of dipentaerythritol and propylene oxide. The latter polyether polyol had a molecular weight of about 675 and a hydroxyl number of 497. The reaction mixture was heated at 7983 C. for 9 hours. Thereafter, an additional 135 grams of triethylamine were added, and the mixture heated at about 80 for an additional 6 hours. During the reaction period, nitrogen was bubbled through the system. To the mixture was added 10.5 grams of diatomaceous earth, followed by filtration. The filtrate was stripped by heating at 7080 under vacuum while passing nitrogen therethrough to obtain the desired product.

EXAMPLE V In this example, a substituted phosphorarnidate was prepared from an a-methyl glucoside-propylene oxide adduct having a molecular weight of about 512 and a hydroxyl number of about 439. 1530 grams of the polyol,

512 grams of bis(dimethylamido)phosphorochloridate, 39 grams of activated carbon and 607 grams of triethylamine were charged to a reaction flask. Nitrogen was passed through the mixture which was heated to a temperature of about 75-85 C. for a period of about 14 hours. After addition of 20 grams of diatomaceous earth, the mixture was filtered through a Buchner funnel having a diatomaceous earth bed. The filtrate was stripped at C., 2 mm. Hg pressure for 4 hours. 1140 grams of the desired product were obtained.

EXAMPLE VI 1060 grams of Pluracol SP Polyol560, 1024 grams of bis(dimethylarnido)phosphorochloridate and 810 grams of triethylamine were charged to a reaction flask. Nitrogen was bubbled through the system and the reaction mass was heated at about 80 C. for a period of about 13 hours when an additional 810 grams of triethylamine was charged. The mixture was heated for an additional 5 hours at 80 and then filtered through a Buchner funnel having a diatomaceous earth bed. The filtrate was stripped by heating at about 80 C., 2-7 mm. Hg pressure for 2 /2 hours. 826 grams of the desired product having 5 hydroxyl groups was obtained.

EXAMPLE VII 1144 grams of a sucrose-glycerine polyether polyol having a molecular weight of about 572 and a hydroxyl number of 488, 512 grams of bis(dimethylamido)phosphorochloridate, 15 grams of activated carbon and 400 grams of triethyleneamine were charged to a reaction flask. The foregoing polyether polyol was obtained by condensing a 2.5 :1 sucrose-glycerine mixture with propylene oxide. Nitrogen was bubbled through the mixture which was heated at 60-75 C. for 3 hours. An additional 227 grams of triethylamine were added and the mixture was heated at 80 for 6 hours. The material was filtered to obtain the desired product.

EXAMPLE VIII This example illustrates the preparation of a substituted phosphoramidate polyol of this invention by reaction of the potassium alkoxide of a polyether polyol with his (dimethylamido)phosphorochloridate. 1028 grams of Polyol SP560 were charged to a reaction flask equipped with a stirrer, thermometer, gas entry means and condensing means. A mixture consisting of 112 grams of potassium hydroxide dissolved in 262 grams of 60% methanol was added to the SP-560 at a temperature of about 50 C. The mixture was then stripped at C. to remove methanol and water and 228 grams of his (dimethylamido)phosphorochloridate were added. An exotherm was evident, the temperature of the reaction being in the range of 107147 C. An additional 114 grams of bis(dimethylamido)phosphorochloridate were added to complete the reaction. The solution was a milky white due to the precipitated potassium chloride. The material was then filtered through a diatomaceous earth bed and stripped by heating for 1 /2 hours at 95-100 C. at 2 mm. Hg pressure. 1042 grams of the desired product were obtained.

EXAMPLE IX To a reaction flask was added 341 grams of bis(dimethylamido)phosphorochloridate and 270 grams of triethylamine and 680 grams of Pluracol TP-340. This latter material is a trifunctional polyol obtained 'by condensing trimethylolpropane with propylene oxide in the presence of an alkaline catalyst. The product, having an average molecular weight of 300 and a hydroxyl number of 561 is commercially available from Wyandotte Chemicals Corporation. After about 3 /2 hours heating at 6574 C., an additional grams of triethylamine were added to the reaction mass. During the reaction, nitrogen Was bubbled through the system. The mixture was then heated at 74-82 for an additional 1% hours, cooled and filtered to remove the triethylamine hydrochloride precipitate. The filtrate was heated for an additional 7 hours at 70- 80 C., refiltered, and stripped at a temperature under 87 C. 890 grams of an amber-colored liquid having an average of two hydroxyl groups was obtained. The product was soluble in methanol, ethylene dichloride, isopropanol, benzene, toluene, acetone, xylene, Freon 11, trimethylolpropane, toluene diisocyanate, and water, and was insoluble in hexane and petroleum ether. An infrared spec trum provided ample evidence for the structure:

wherein (TP-340) contains two hydroxyl groups and together with attached oxygen is the residue of Pluracol TP-340 polyether described above.

EXAMPLE X EXAMPLE XI 1352 grams of a polyol having a hydroxyl number of 249 and prepared by the reaction of trimethylolpropane with a mixture of equal weights of propylene oxide and 1,2butylene oxide, 238 grams of N-phenyl-N-ethylphosphorodichloridate and 210 grams of triethylamine are charged to a reaction flask. Nitrogen is bubbled through the system and the reaction mass is heated at 80-85 C. for about 14 hours, after which time 300 grams additional triethylamine are added.

The mixture is heated for an additional 4 hours and filtered. The filtrate is stripped of volatile components by heating at about 80 C. and 2-10 mm. Hg pressure for 2 hours. The desired product is in the form of a dark colored viscous liquid.

EXAMPLE XII In this example, a substituted phosphoramidate is prepared from a sucrose-butylene oxide adduct having a molecular weight of about 825 and a hydroxyl number of 549. 1237 grams of the polyol, 340 grams of bis(diethylamido)phosphorochloridate, 40 grams of activated carbon and 304 grams of triethylamine are charged to a reaction flask. Nitrogen is passed through the mixture which is heated to a temperature of about 80 C. for a period of about 15 hours. The mixture is filtered through a Buchner funnel having a diatomaceous earth pre-coat or bed. The filtrate is stripped at 80 C. and 2-5 mm. Hg pressure for 3 hours leaving a dark, viscous liquid.

EXAMPLE XIII 1050 grams of a sucrose polyether polyol having a hydroxyl number of 428 is reacted with 130 grams of N4- chlorophenyl-N-methylphosphorodichloridate in the presence of 800 grams of tri-n-propylamine. The foregoing polyether polyol was the product of a 75-25 weight percent mixture of propylene oxide and ethylene 8 oxide reacted with sucrose. Nitrogen is bubbled through the mixture which is heated at C. for 3.5 hours. An additional 300 grams of the tri-n-propylamine are added and the mixture heated at C. for .8 hours.

The reaction mass is filtered and stripped in the usual manner to obtain the desired product.

EXAMPLE XIV 1000 grams of a pentaerythritol polyoxypropylene polyether having a hydroxyl number of 56 and a molecular weight of 4000 are reacted with 43 grams of bis-(dimethylamido)phosphorochloridate in the presence of 101 grams of triethylamine as an acid acceptor and by the procedure described in Example V. The pentaerythritol polyether used in this preparation is the reaction product of propylene oxide and pentaerythritol.

We claim: 1.v Phosphoramidates represented by the formulae Ii R o P(OY)2-n where R, together with attached oxygen, is theresidue of a polyol selected from the group consisting of organic polyols containing at least 2 hydroxyl groups per molecule and polyethers of said organic polyols; R and R individually represent a hydrocarbon group selected from alkyl, aryl, cycloalkyl, alkaryl, aralky-l containing up to about 12 carbon atoms and the foregoing hydrocarbons containing halogen substituents selected from chlorine and bromine; n is a number from 1 to 2; m1 is a number from 0 to about 7 and is equal to the number of hydroxyl groups present in polyol residue R; f is an integer greater than 1 and is equal to the number of hydroxyl groups originally present in said polyol; and m:) is equal to at least 1; Y is selected from the group consisting of R containing (f-l) hydroxyl groups, and

where R, R, R", Y, 1 and n have the same significance as stated above, said phosphoramidatecontaining at least one hydroxyl group in the molecule.

2. The phosphoramidates of claim 1 wherein R is the residue of a polyether polyol containing from 3 to about 8 hydroxy groups per molecule and having a molecular weight of from about 200 to 7000, and n is equal to l.

3. The phophoramidate of claim 2 wherein R and R" are the same and are alkyl radicals containing 1 to about 8 carbon atoms, (f-m) isequal to 1 and Y represents R.

4. Phosphoramidates represented by the formula:

wherein R together with attached oxygen is the residue of a polyol selected from the group consisting of polyhydroxyl alkanes containingfrom 3 to 8 hydroxyl groups, monoand disaccharides containing from 5 to 8 hydroxyl groups,.and monoand polyethers of the foregoing wherein said polyol has a molecular weight of from about to 5,000, and R and R" are the same or different and are selected from the group consisting of alkyl, cycloalkyl, aryl, aralkyl, and alkaryl radicals containing up to about 12 carbon atoms, m is an integer equal to 2-7, inclusive, is an integer from-3 to 8 and is equal to the number of hydroxyl groups originally present in said polyol.

5. The phosphoramidates of claim 4 wherein R is the residue of a polyether polyol obtained by condensing a polyol selected from the group consisting of polyhydroxyl alkanes containing 3 to 8 hydroxy groups and monoand disaccharides containing 5 to 8 hydroxyl groups in the molecule with at least 1 mol of an alkylene oxide per hydroxyl group of said polyol and wherein said alkylene oxide is selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, dichloropropylene oxide, trichloropropylene oxide, and mixtures thereof.

6. The phosphoramidates of claim 5 wherein R and R" are the same and are alkyl radicals containing from 1 to about 8 carbon atoms, and '(f-m) is equal to 1.

7. The phosphorarnidates of claim 6 wherein said alkylene oxide is a vicinal alkylene oxide and contains from 2 to 4 carbon atoms.

8. Phosphoramidates represented by the formula:

where R contains 2 to 7 hydroxyl groups and together with attached oxygen is the residue of a polyether polyol having a molecular weight of from about 300 to 5,000 and obtained by condensing a polyol selected from the group consisting of polyhydroxyl alkanes containing from 3 to 8 hydroxyl groups and monoand disaccharides containing from 5 to 8 hydroxyl groups per molecule with at least 1 mol of a vicinal alkylene oxide per hydroxyl group of said polyol, said alkylene oxide being selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, dichloropropylene oxide, trichloropropylene oxide, and mixtures thereof.

9. Phosphoramidates of claim 8 wherein said polyether polyol is obtained by condensing sorbitol with propylene oxide.

10. The phosphoramidate of claim 8 wherein said polyether polyol is obtained by condensing pentaerythritol with propylene oxide.

11. The phosphoramidate of claim 8 wherein said polyether polyol is obtained by condensing a-methyl glucoside with propylene oxide.

12. The phosphoramidate of claim 8 wherein said polyether polyol is obtained by condensing sucrose with propylene oxide.

References Cited UNITED STATES PATENTS 3,018,302 1/1962 Arnold et a1. 260953 3,035,080 5/1962 Arnold et a1. 260953 LEWIS GOTIS, Primary Examiner.

JOHNIE R. BROWN, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 ,335 ,129 August 8 1967 Herwart C. Vogt et al.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 9, lines 16 tol9,. the formula should appear as shown below instead of as in the patent:

N U- OR (311/ column 9, lines 23 and 24, strike out "having a molecular weight ofv from. about 300 t 5,000 and" and insert the same after "polyol" in line 24, same column 9.

Signed and sealed this 18th day of June 1968.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. EDWARD J. BRENNER Attesting Officer Commissioner of Patents 

4. PHOSPHORAMIDATES REPRESENTED BY THE FORMULA: 